Clinical evaluation of a patient infected with HIV virus (Acquired Immunodeficiency Syndrome; AIDS) currently relies on physician evaluation of patient status in conjunction with quantitation of T-cell lymphocytes present in the patient's blood. Such cell counts, though reflecting the gross progression of the disease, do not provide specific information concerning either the functional status of the patient's immune system nor the efficacy of particular therapeutic agents in treating the infection, since T-cells comprise a heterogeneous mixture of cell types. There are at least two major subsets of T-cells, termed CD4 and CD8.
Recently, investigators have developed assays which employ fluorescently tagged monoclonal antibodies to specific cell antigens and Fluorescence Activated Cell Sorting (FACS) to determine the relative proportions of the various lymphocyte classes in a patient's blood. Such assays have shown that HIV viral infection differentially affects the various blood cell types. Persons infected with the HIV virus, and particularly those persons characterized as having Acquired Immune Deficiency (AIDS) or Aids Related Complex (ARC) have been shown to have reduced numbers of CD4 cells and, in many cases, elevated proportions of CD8 cells.
In evaluating treatments and/or therapies for AIDS, as well as in determining which existing therapies are most appropriate for a particular AIDS patient, it is important to have an accurate measure of the extent of the disease (i.e., the stage to which the disease has progressed) in the subjects under evaluation, so that results of such studies can be interpreted in a meaningful manner. Such "staging" information has historically been inferred from the total CD4+ T lymphocyte (T cell) counts, which are known to fall progressively as the disease advances.
As is disclosed below, however, the use of total CD4+ T cell counts as a measure of the advancement of AIDS fails to detect aspects and consequences of the disease that are important in the choice of therapies at particular stages, and the evaluation of the effectiveness of experimental therapies.
The present invention provides methods of staging the advancement or progress of AIDS, as well as other diseases and/or conditions affecting the function of the immune system, that are more useful and accurate than total CD4 T cell counts.